The open flow is a communication technique which carries out a route control in units of flows. In the open flow, a “flow” is determined based on a combination of MAC addresses, IP addresses, and port numbers and so on. In the open flow technique, a route is not determined uniformly based on a source node and a destination node. In the open flow technique, a route can be changed between the source node and the destination node for every flow. Also, the route can be managed in an End-to-End system (between termination nodes) in addition to a system between the neighbor nodes. As a related art of the open flow technique, Non-Patent Literature 1 is known.
On the other hand, the demand of a high-speed large-capacity auxiliary storage apparatus is rising with the advance of a computer system. Especially, in case of handling a large-scale computer system, a configuration in which a storage (a disk array) as a set of storage apparatuses is connected with SAN (storage area network) is used in many cases. The iSCSI is well-known as a protocol using a SCSI (Small Computer System Interface) command through a network. The SAN using the iSCSI is commercially focused in a market to develop largely in the future from the viewpoint of a relatively cheap apparatus cost, and an effective use of an existing infrastructure.
As a related art in the SAN using the iSCSI, Japanese Patent Publication (JP 2004-164490A (Patent Literature 1)) is known. In JP 2004-164490A, a technique is disclosed in which the allocation of a storage to a host is carried out without changing the setting of a storage router, by using a virtual host identifier in the iSCSI storage system.
The SAN using the iSCSI uses TCP/IP (Transmission Control Protocol/Internet Protocol) in a lower layer of the SCSI. An open flow switch using the present open flow technique can handle only protocols up to the TCP layer in layer 4 in the OSI Reference Model. Because the iSCSI layer is in the layer 4 of the OSI Reference Model but is in an upper layer than the TCP layer, the iSCSI layer cannot be recognized by the open flow switch using the open flow technique. Therefore, the present open flow switch cannot control a flow by directly referring to SCSI names (iSCSI initiator name and iSCSI target name) of iSCSI layer data contained in the packet. The open flow switch which can handle data in the iSCSI layer is needed in order to realize the more flexible flow control.